Botanically called Lactuca sativa, lettuce, a leafy vegetable, belongs to the Asteraceae family. Lettuce has been traditionally used for relieving pain, inflammation, insomnia, anxiety, neurosis, dry coughs, rheumatic pain, stomach problems including indigestion and lack of appetite. Moreover, the therapeutic significance of lettuce includes its anticonvulsant, sedative-hypnotic and antioxidant properties.

Thromboembolism is the formation in a blood vessel of a clot (thrombus) that breaks loose and is carried by the blood stream to plug another vessel. The study published in BMC Complement Alternative Medicine is titled “Evaluation of analgesic, anti-inflammatory, anti-depressant and anti-coagulant properties of Lactuca sativa (CV. Grand Rapids) plant tissues and cell suspension in rats.”

“More interestingly, cell suspension exudate showed prominent results in all the assays which is the main point of interest because valuable secondary metabolites and economically important substances can be produced in bulk from plant cell suspensions in simple, cost-effective and reproducible way. However, advance study is needed to explore the precise mechanism of action the active components.”

Several studies have shown that the function of the anticoagulant drugs is to inhibit blood clotting, which is the major cause of heart attacks and strokes. Anticoagulant drugs can be used with a number of diseases when there is a high risk of blood clots. The researchers said that since anti-coagulants are used for the cardiac problems, instead of relying on blood thinners, physicians could shift to herbal medicine. It has been reported that antioxidants can counteract the haematological and blood coagulation disturbances, oxidative stress, and hepatorenal (liver and kidney) damages.

The researchers added: “Anticoagulants play an essential role as mediators for the treatment and prevention of thromboembolic disorders. Due to their pharmacological possessions, plants can serve as the sources for the investigation of new compounds with anticoagulant properties. There is convincing scientific indications representing that the use of phytochemicals with anticoagulant effects and dietary anticoagulants can eventually eliminate or reduce the risks of thromboembolic diseases.

“Here we report the L. sativa a herbal drug for its analgesic, anti-inflammatory, anti-depressant and anti-coagulant activities of the seeds and leaf extracts along with the cell suspension exudate. We obtained very interesting and promising results which elucidate the importance of lettuce as a traditional medicine.”

The current findings showed that aqueous and methanol and chloroform; 1:1 (MC) extracts of seed have the least immobility time in the forced swimming test, which could act as an anti-depressant on the central nervous system. The leaf extracts and cell suspension exudate also expressed moderate anti-depressant activities. In anticoagulant assay, the coagulation time of aspirin (positive control) and MC extract of leaf was comparable, suggesting strong anti-coagulant effect. Additionally, no abnormal behaviour or lethality was observed in any animal tested.

“Conversely, if a condition such as an inflammation of the paw, serves to decrease the response latency, it is said to induce hyperalgesia. Inflammation is a condition involving confined increase in the amount of leukocytes and various complex mediator molecules. The most common screening method of acute inflammation has been the prevention of edema in rats by induction of carrageenan. It is believed that the COX (cyclooxygenase) enzyme involved in inflammation can be inhibited by NSAIDs (Nonsteroidal anti-inflammatory drugs) to reduce the edema. But NSAIDs have some side effects like renal and gastric toxicity. Medicinal plants are believed to be cost-effective and harmless source of novel biochemical constituents with strong therapeutic properties.”

Hyperalgesia is an increased sensitivity to pain, which may be caused by damage to nociceptors or peripheral nerves. Also, researchers have also successfully used lettuce to reduce anxiety (anxiolytic).

The study titled “Anxiolytic property of Lactuca sativa, effect on anxiety behaviour induced by novel food and height” was published in Asian Pacific Journal of Tropical Medicine.

They further explained: “The hydro alcohol extract rich in polyphenols and other secondary metabolites is a potent anxiolytic agent. It has been established that there are lot of plant secondary metabolites like polyphenols and flavonoids being employed in the treatment of psychotic disorders especially for anxiety in traditional medicine practice, most of which directly or indirectly affect the central nervous system.

“Considering the varied important activities reported in traditional system of medicine about L. sativa, it was planned to study the effects of the extract of

L. sativa leaves on anxiolytic properties in mice. Although anxiety is an important protective mechanism, it can become maladaptive and disruptive.
“Pathological anxiety, as manifested in anxiety disorders, is an anxious response that occurs out of proportion to the threat, becomes disruptive to daily life and causes suffering. Anxiety has been implicated in a number of psychiatric disorders, such as generalized anxiety disorder, depression, panic-attacks, phobias, obsessive-compulsive disorders and posttraumatic stress disorders.

“Anxiety alleviates the levels of intracellular reactive oxygen species. Anxiety induces stress and activates the sympathetic nervous system, stimulating the release of catecholamines from the adrenal medulla as a response to stressors fight or flight.

Benzodiazepine, the most commonly prescribed treatment for anxiety disorders, has side effects such as sedation, myorelaxation, ataxia, amnesia and pharmacological dependence. Hence various plants are used in complementary and alternative medicines for management of anxiety.”

Another study published in Academic Journals and African Journal of Pharmacology has validated the neuro-protective effect of Lactuca sativa on glucose/serum deprivation-induced cell death or rather brain ischemia (stroke).

The researchers are from: Neuroscience Research Center, Department of Pharmacology, School of Medicine, Mashhad University of Medical
Sciences, Mashhad, Iran; Neyshabur Faculty of Medical Sciences, Neyshabur, Iran; and Pharmacological Research Center of Medicinal Plants, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.

Brain ischemia (a.k.a. cerebral ischemia, cerebrovascular ischemia) is a condition in which there is insufficient blood flow to the brain to meet metabolic demand. This leads to poor oxygen supply or cerebral hypoxia and thus to the death of brain tissue or cerebral infarction / ischemic stroke.

Mechanisms of cell damage include apoptosis, acidosis, inflammation, excitotoxicity and oxidative stress. The brain is especially sensitive to oxidative damage due to its high rate of oxidative metabolic activity and to having relatively low levels of endogenous antioxidants.

Therefore, a promising approach to neuro-protection against brain ischemia and other neurodegenerative disorders is the use of antioxidants and anti-inflammatory agents.

At present, there are very few medications for the management of brain ischemia, with limited success. Therefore, the search for new therapeutics has been continued.

Recently, it has been showed that L. sativa protect neuron-like rat pheochromocytoma-derived cell line (PC12) cells against H2O2-induced cytotoxicity via antioxidant activity. Also, neuro-protective effects of this plant have been demonstrated in the mice subjected to D-galactose-induced oxidative brain damage.

The researchers concluded: “Our data showed, for the first time, that L. sativa can protect neurons against ischemic condition… Regardless of the exact compounds responsible for this neuro-protective activity, we conclude it is possible that L. sativa has the potential to be used as a new therapeutic strategy for common neurological disorders such as brain ischemia.”